Patent US5629237A successfully refreshed from Google Patents.
US5629237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Taper etching without re-entrance profile
Assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
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Filing: 1995-10-19
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Granted: 1997-05-13
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Expires: 2015-10-19
Abstract
Abstract A method is described for forming tapered contact via holes in large scale integrated circuit structures which avoids the formation of a re-entrance profile. The re-entrance profile can form at the entrance to the contact via hole when a dry etch is used as a first etching step by redepositing material removed during the dry etch at the entrance of the contact via hole. This re-entrance profile makes the angle of entrance into the contact via hole greater than 90° and the step coverage of metal filling the hole poor. This invention uses wet etching with a greater lateral etch rate than vertical etch rate as a first etching step in the formation of the contact via hole and avoids the formation of the re-entrance profile. The edges of the resulting contact via hole are smooth and the entrance angle into the contact via hole is substantially less than 90°. The step coverage of metal later filling the contact via hole is substantially improved.
Inventors
- 👤 Pei-Jan Wang
- 👤 Kuei-Lung Chou
- 👤 Jiunn-Jyi Lin
- 👤 Hsien-Wen Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:14
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081; H10W20/082; Y; Y10; Y10S; Y10S438/00; Y10S438/978
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
190 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and an insulating layer over said semiconductor substrate; forming a photoresist masking layer over said insulating layer; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said insulating layer through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a first dry anisotropic etch, into said insulating layer through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said insulating layer through a third thickness, thereby forming a third via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a second dry anisotropic etch, through the remainder of said insulating layer, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 2
Independent Claim
190 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and an insulating layer over said semiconductor substrate; forming a photoresist masking layer over said insulating layer; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said insulating layer through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a first dry anisotropic etch, into said insulating layer through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said insulating layer through a third thickness, thereby forming a third via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a second dry anisotropic etch, through the remainder of said insulating layer, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein said insulating layer is borophosphosilicate glass with a thickness of between about 7500 and 9000 Angstroms.
Claim 4
Dependent Claim
25 words
The method of claim 1 wherein said opening in said photoresist masking layer is circular with a diameter of between about 0.7 and 1.0 microns.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said first dry anisotropic etch is accomplished by means of ion bombardment.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein said dry isotropic etch is accomplished by means of plasma etching.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein said second dry anisotropic etch is accomplished by means of ion bombardment.
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein said first thickness is between about 500 and 1000 Angstroms.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein said second thickness is between about 2500 and 3000 Angstroms.
Claim 10
Dependent Claim
16 words
The method of claim 1 wherein said third thickness is between about 1000 and 1500 Angstroms.
Claim 11
Dependent Claim
22 words
The method of claim 1 wherein said insulating layer is silicon dioxide with a thickness of between about 7500 and 9000 Angstroms.
Claim 12
Dependent Claim
21 words
The method of claim 1 wherein said insulating layer is glass with a thickness of between about 7500 and 9000 Angstroms.
Claim 13
Independent Claim
175 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and a layer of borophosphosilicate glass having a thickness of between about 5000 and 9000 Angstroms over said semiconductor substrate; forming a photoresist masking layer over said layer of borophosphosilicate glass; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said layer of borophosphosilicate glass through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said layer of borophosphosilicate glass through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a dry anisotropic etch, through the remainder of said layer of borophosphosilicate glass, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 14
Independent Claim
175 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and a layer of borophosphosilicate glass having a thickness of between about 5000 and 9000 Angstroms over said semiconductor substrate; forming a photoresist masking layer over said layer of borophosphosilicate glass; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said layer of borophosphosilicate glass through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said layer of borophosphosilicate glass through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a dry anisotropic etch, through the remainder of said layer of borophosphosilicate glass, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 15
Independent Claim
175 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and a layer of silicon dioxide having a thickness of between about 7500 and 9000 Angstroms over said semiconductor substrate; forming a photoresist masking layer over said layer of silicon dioxide; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said layer of silicon dioxide through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said layer of silicon dioxide through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a dry anisotropic etch, through the remainder of said layer of silicon dioxide, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 16
Independent Claim
175 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and a layer of silicon dioxide having a thickness of between about 7500 and 9000 Angstroms over said semiconductor substrate; forming a photoresist masking layer over said layer of silicon dioxide; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said layer of silicon dioxide through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said layer of silicon dioxide through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a dry anisotropic etch, through the remainder of said layer of silicon dioxide, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 17
Independent Claim
170 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and a layer of glass having a thickness of between about 7500 and 9000 Angstroms over said semiconductor substrate; forming a photoresist masking layer over said layer of glass; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said layer of glass through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said layer of glass through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a dry anisotropic etch, through the remainder of said layer of glass, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
Claim 18
Independent Claim
170 words
A method of forming tapered contact via holes, comprising the steps of: providing an integrated circuit structure having device elements within a semiconductor substrate, contact areas in said semiconductor substrate, and a layer of glass having a thickness of between about 7500 and 9000 Angstroms over said semiconductor substrate; forming a photoresist masking layer over said layer of glass; forming openings in said photoresist masking layer directly over said contact areas; wet etching into said layer of glass through a first thickness, thereby forming a first via hole opening, using said photoresist masking layer as a mask; isotropically etching, by means of a dry isotropic etch, into said layer of glass through a second thickness, thereby forming a second via hole opening, using said photoresist masking layer as a mask; vertically anisotropically etching, by means of a dry anisotropic etch, through the remainder of said layer of glass, thereby forming said tapered contact via hole opening, using said photoresist masking layer as a mask; and removing said photoresist masking layer.
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